This invention relates to corner connectors for use in sliding door assemblies.
In a widely used form of sliding door used for closets and other fairly light-duty applications, the door is formed by a relatively thin panel of hardboard or similar material, with a suitable decorative facing, or by a mirror, to the edges of which are applied metallic stiles and rails linked by top and bottom corner connectors which also support and guide the door for sliding movement along top and bottom tracks fixed in a door opening. The top connectors have upwardly projecting arms carrying rollers which suspend the door from the upper rail, whilst the bottom connectors have downwardly projecting arms terminating in guide members or rollers which engage the lower rail and maintain the door in the desired plane whilst accommodating some degree of irregularity in the vertical spacing of the top and bottom tracks.
Progressively improved versions of such corner connectors are described in detail in U.S. Pat. No. 3,058,173 (Brydolf), and Canadian Pat. Nos. 844,876 (Kellems) and 978,805 (Brydolf et al). The structure of the Kellems patent not only links the stiles and rails, but also draws them together during assembly and largely eliminates the need for screws, rivets or other separate fastenings to secure the parts together. It requires however a different connector of each corner of the panel, and is relatively expensive to manufacture. The Brydolf et al Canadian patent discloses a connector which, whilst having somewhat less rigid interlocking with the stiles than the Kellems patent, and requiring a different form of stile, is cheaper to manufacture, and can be used on either side of a panel.
U.S. Pat. No. 4,391,019 (Downes) discloses a corner connector bracket which permits the suspension arms or guides to be detachable, so that the same bracket can be used at both the top and the bottom of a panel, whilst U.S. Pat. No. 3,744,827 (Cox) discloses corner connectors using a bracket which is reversible end to end. A modification of the Cox connector, available commercially, is also bilaterally symmetrical. Although this connector makes multipoint contact with the panel, it is only restrained at the stile against movement away from the panel; its resistance to torsional movement is thus dependent on the torsional stiffness of the stile, which is relatively low.
All of these various corner connector arrangements hold together the stiles and rails at the corners of a sliding door with varying but generally adequate degrees of effectiveness, although in some cases requiring stiles of specific section. A further requirement of such corner connectors is that they maintain the arms carrying the rollers or guides for the door in correct alignment relative to the door panel. This is important for maintaining free running of the door, and is a requirement which in general has not been fully met by existing designs because the flexibility of the rail and stile profiles needed to provide for different panel thicknesses results in inadequate resistance to torsional movement of the brackets and thus the arms.
One arrangement which overcomes this problem is the Leigh Snap-Fit Door, described in a brochure issued under that title by Leigh Products Inc. of Coopersville, Mich. This door assembly relies upon corner brackets adhesively secured to the panel, the stiles and rails being snap fitted to the corner brackets. In this arrangement, the rails and stiles are not positively locked together into a perimeter frame, and take little part sustaining the weight of the door and operating forces, which are largely borne through the adhesive bonds by the corners of the panel. The arrangement of the Brydolf U.S. Pat. No. 3,058,173 also overcomes the problem, but relies upon the use of now obsolete stile and rail sections, and requires to be screwed and staked in place.